Medical probe device and method relationship to copending application

ABSTRACT

A medical probe device comprises a catheter having a stylet guide housing with one or more stylet ports in a side wall thereof and a stylet guide for directing a flexible stylet outward through the stylet port and through intervening tissue at a preselected, adjustable angle to a target tissue.  
     The total catheter assembly includes a stylet guide lumen communicating with the stylet port and a stylet positioned in said stylet guide lumen for longitudinal movement from the port through intervening tissue to a target tissue. The stylet can be an electrical conductor enclosed within a non-conductive layer, the electrical conductor being a radiofrequency electrode. Preferably, the non-conductive layer is a sleeve which is axially moveable on the electrical conductor to expose a selected portion of the electrical conductor surface in the target tissue. The stylet can also be a microwave antenna. The stylet can also be a hollow tube for delivering treatment fluid to the target tissue. It can also include a fiber optic cable for laser treatment. The catheter can include one or more inflatable balloons located adjacent to the stylet port for anchoring the catheter or dilation. Ultrasound transponders and temperature sensors can be attached to the probe end and/or stylet. The stylet guide can define a stylet path from an axial orientation in the catheter through a curved portion to a lateral orientation at the stylet port.

RELATIONSHIP TO COPENDING APPLICATION

[0001] This application is a continuation-in-part of copendingapplication Ser. No. 07/929,638 filed Aug. 12, 1992.

FIELD OF THE INVENTION

[0002] This invention is directed to a unique device and method forpenetrating body tissues for medical purposes such as tissue destructionand fluid substance delivery, for example. The device penetrates tissueto the precise target selected in order to deliver energy to the tissueand/or deliver substances. It limits this activity to the precisepreselected site, thereby minimizing trauma to normal surrounding tissueand achieving a greater medical benefit. This device is a catheter-likedevice for positioning a treatment assembly in the area or organselected for medical treatment with one or more stylets in the catheter,mounted for extension from a stylet port in the side of the catheterthrough surrounding tissue to the tissue targeted for medical activity.

BACKGROUND OF THE INVENTION

[0003] Treatment of cellular tissues usually requires direct contact oftarget tissue with a medical instrument, usually by surgical proceduresexposing both the target and intervening tissue to substantial trauma.Often, precise placement of a treatment probe is difficult because ofthe location of a target tissue in the body or the proximity of thetarget tissue to easily damaged, critical body organs, nerves, or othercomponents.

[0004] Benign prostatic hypertrophy or hyperplasia (BPH), for example,is one of the most common medical problems experienced by men over 50years old. Urinary tract obstruction due to prostatic hyperplasia hasbeen recognized since the earliest days of medicine. Hyperplasticenlargement of the prostate gland often leads to compression of theurethra, resulting in obstruction of the urinary tract and thesubsequent development of symptoms including frequent urination,decrease in urinary flow, nocturia, pain, discomfort, and dribbling. theassociation of BPH with aging has been shown to exceed 50% in men over50 years of age and increases in incidence to over 75% in men over 80years of age. Symptoms of urinary obstruction occur most frequentlybetween the ages of 65 and 70 when approximately 65% of men in this agegroup have prostatic enlargement.

[0005] Currently there is no proven effective nonsurgical method oftreatment of BPH. In addition, the surgical procedures available are nottotally satisfactory. Currently patients suffering from the obstructivesymptoms of this disease are provided with few options: continue to copewith the symptoms (i.e., conservative management), submit to drugtherapy at early stages, or submit to surgical intervention. More than430,000 patients per year undergo surgery for removal of prostatictissue in the United States. These represent less than five percent ofmen exhibiting clinical significant symptoms.

[0006] Those suffering from BPH are often elderly men, many withadditional health problems which increase the risk of surgicalprocedures. Surgical procedures for the removal of prostatic tissue areassociated with a number of hazards including anesthesia associatedmorbidity, hemorrhage, coagulopathies, pulmonary emboli and electrolyteimbalances. These procedures performed currently can also lead tocardiac complications, bladder perforation, incontinence, infection,urethral or bladder neck stricture, retention of prostatic chips,retrograde ejaculation, and infertility. Due to the extensive invasivenature of the current treatment options for obstructive uropathy, themajority of patients delay definitive treatment of their condition. Thiscircumstance can lead to serious damage to structures secondary to theobstructive lesion in the prostate (bladder hypertrophy, hydronephrosis,dilation of the kidney pelves, etc.) which is not without significantconsequences. In addition, a significant number of patients withsymptoms sufficiently severe to warrant surgical intervention are pooroperative risks and are poor candidates for prostatectomy. In addition,younger men suffering from BPH who do not desire to risk complicationssuch as infertility are often forced to avoid surgical intervention.Thus the need, importance and value of improved surgical andnon-surgical methods for treating BPH is unquestionable.

[0007] High-frequency currents are used in electrocautery procedures forcutting human tissue especially when a bloodless incision is desired orwhen the operating site is not accessible with a normal scalpel butpresents an access for a thin instrument through natural body openingssuch as the esophagus, intestines or urethra. Examples include theremoval of prostatic adenomas, bladder tumors or intestinal polyps. Insuch cases, the high-frequency current is fed by a surgical probe intothe tissue to be cut. The resulting dissipated heat causes boiling andvaporization of the cell fluid at this point, whereupon the cell wallsrupture and the tissue is separated.

[0008] Destruction of cellular tissues in situ has been used in thetreatment of many diseases and medical conditions alone or as an adjunctto surgical removal procedures. It is often less traumatic than surgicalprocedures and may be the only alternative where other procedures areunsafe. Ablative treatment devices have the advantage of using adestructive energy which is rapidly dissipated and reduced to anondestructive level by conduction and convection forces of circulatingfluids and other natural body processes.

[0009] Microwave, radiofrequency, acoustical (ultrasound) and lightenergy (laser) devices, and tissue destructive substances have been usedto destroy malignant, benign and other types of cells and tissues from awide variety of anatomic sites and organs. Tissues treated includeisolated carcinoma masses and, more specifically, organs such as theprostate, glandular and stromal nodules characteristic of benignprostate hyperplasia. These devices typically include a catheter orcannula which is used to carry a radiofrequency electrode or microwaveantenna through a duct to the zone of treatment and apply energydiffusely through the duct wall into the surrounding tissue in alldirections. Severe trauma is often sustained by the duct wall duringthis cellular destruction process, and some devices combine coolingsystems with microwave antennas to reduce trauma to the ductal wall. Fortreating the prostate with these devices, for example, heat energy isdelivered through the walls of the urethra into the surrounding prostatecells in an effort to kill the tissue constricting the urethra. Lightenergy, typically from a laser, is delivered to prostate tissue targetsites by “burning through” the wall of the urethra. Healthy cells of theduct wall and healthy tissue between the nodules and duct wall are alsoindiscriminately destroyed in the process and can cause unnecessary lossof some prostate function. Furthermore, the added cooling function ofsome microwave devices complicates the apparatus and requires that thedevice be sufficiently large to accommodate this cooling system.

[0010] Application of liquids to specific tissues for medical purposesis limited by the ability to obtain delivery without traumatizingintervening tissue and to effect a delivery limited to the specifictarget tissue. Localized chemotherapy, drug infusions, collageninjections, or injections of agents which are then activated by light,heat or chemicals would be greatly facilitated by a device which couldconveniently and precisely place a fluid supply catheter opening at thespecific target tissue.

OBJECTS AND SUMMARY OF THE INVENTION

[0011] It is the principal object of this invention to provide a deviceand method for penetrating tissue, through intervening tissues to theprecise target tissue selected for a medical action such as tissuedestruction and/or substance delivery, limiting this activity to theprecise preselected site, thereby minimizing the trauma and achieving agreater medical benefit.

[0012] One principal object of this invention is to provide a device andmethod for tissue destruction of body tissues which delivers thetherapeutic energy directly into a target tissue while minimizingeffects on its surrounding tissue.

[0013] Another principal object of this invention is to provide a deviceand method for introducing fluid treatment agents, particularly flowableliquids, with greater precision and ease to a specific location in thebody.

[0014] Another object of this invention is to provide a thermaldestruction device which gives the operator more information about thetemperature and other conditions created in both the tissue targeted fortreatment and the surrounding tissue. In addition, it will provide morecontrol over the physical placement of the stylet and over theparameters of the tissue destruction process.

[0015] In summary, the medical probe device of this invention comprisesa catheter having a control end and a probe end. The probe end includesa stylet guide housing having at least one stylet port in a side wallthereof and guide means for directing a flexible stylet outward throughthe stylet port and through intervening tissue at a preselected angle toa target tissue. The housing can include an array of such ports. Thepreselected angle is preferably from 200 to 1600 with the central axisof the stylet guide housing. The total catheter assembly includes one ormore stylet guide lumena communicating with respective stylet ports anda stylet positioned in each of said stylet guide lumena for longitudinalmovement from the respective port through intervening tissue to targettissues.

[0016] The stylet can be an electrical conductor enclosed within anon-conductive layer, the electrical conductor being an radiofrequencyelectrode. Preferably, the non-conductive layer is a sleeve which isaxially or longitudinally moveable on the electrical conductor to exposea selected portion of the electrical conductor surface in the targettissue. The stylet can also be a microwave antenna.

[0017] In a still further embodiment, the stylet is a cannula having alongitudinal, central treatment fluid supply lumen extendingtherethrough, and the catheter has a treatment fluid transport lumencommunicating with the treatment fluid supply lumen.

[0018] An ultrasound reflector such as a bubble or an ultrasoundtransducer can be embedded or otherwise attached to the probe end or aportion of the stylet to provide a signal for use in positioning thecatheter and stylet.

[0019] When the stylet includes a radiofrequency electrode or microwaveantenna, optimally, at least one temperature sensor such as a thermistoror fiber optic cable can be attached to the probe end, stylet guidehousing and/or stylet.

[0020] In one preferred embodiment, the stylet guide defines a styletpath from an axial orientation in the catheter through a curved portionto a lateral orientation at the stylet port, the curved path optionallyhaving a radius which is sufficient to deflect the deployed, extendedstylet to the desired angle, that is, a radius of up to 0.5 cm,depending upon the diameter of the catheter. The stylet guide means candefine a stylet path having a first curved portion extending in adirection away from the stylet port and a second curved portion,continuing from the first curved portion and extending to the styletport.

[0021] For deploying a plurality of stylets, the stylet guide means candefine at least two non-intersecting stylet paths from parallel axialorientations in the catheter through curved portions to lateralorientations at stylet ports, the stylet ports having axes forming anangle of up to 180°. For treating prostate lobes in one embodiment, thestylet port axes form an angle of less than 90° and preferably from 50°to 70°.

[0022] The non-conductive sleeve can comprise a leading tip, a rigidproximal control section, and a flexible portion extending from theleading tip the rigid proximal control section, whereby the sleeve canbe extended through a curved path from an axial orientation to anorientation extending outward through a stylet port. The leading tip canbe tapered inward toward its terminal end. The flexible portion canoptionally be a spiral coil. If the spiral coil is made of conductivematerial, it can be enclosed in an outer non-conductive material.

[0023] The distal portion of the catheter can be more flexible than theproximal portion thereof, facilitating its passage through curved ducts.

[0024] In one embodiment, a control handle is attached to the controlend of the catheter and stylet movement means attached to a stylet andengaging the handle for longitudinal movement of the stylet in thestylet guide means. The stylet movement means comprises manualengagement means for translating manual motion into longitudinal motionof the stylet in the stylet guide means.

[0025] In embodiments where the electrical conductor has axial movementin the non-conductive sleeve, a non-conductive sleeve movement means isattached to a non-conductive sleeve and an electrical conductor movementmeans is attached to the electrical conductor enclosed therein. Thenon-conductive sleeve movement means translates manual motion intolongitudinal motion of the non-conductive sleeve in the stylet guidemeans. The electrical conductor movement means translates manual motioninto longitudinal motion of the electrical conductor in thenon-conductive sleeve. The non-conductive sleeve movement means and theelectrical conductor movement means engage the handle for movementthereon. The non-conductive sleeve movement means and the electricalconductor movement means can include separate, adjacent manual movementmeans, mounted on the handle for both separate and coordinated movementthereon. The housing can have at least two parallel longitudinal slotsthrough a wall thereof, the manual movement means each including afinger engaging surface connected to a slide extending through one ofthe longitudinal slots to a connector in the interior of the housing,the connector being attached to a respective non-conductive sleeve orelectrical conductor.

[0026] The method of this invention for applying destructive energy to atarget tissue comprises first introducing a catheter to a zone adjacentto the tissue to be treated. Then an electrical conductor is moved fromthe catheter through surrounding tissue into a target tissue to bedestroyed. The electrical conductor can be a wire or tube comprising aconductive surface surrounded by a non-conductive sleeve for preventingsignificant transfer of energy from the conductor in tissue surroundingthe sleeve. Heat is generated in the target tissue from an electriccurrent or electromagnetic field produced by the electrical conductor.The volume of tissue being treated is controlled by moving thenon-conductive sleeve to expose a selected length of electrode in thebody tissue to be treated, the remaining area of the electrode remainingshielded by the sleeve to protect the intervening tissues. The amountand duration of the energy delivery is also varied to control the volumeof tissue being treated.

[0027] The electrical conductor can be positioned using a fiber opticviewing system incorporated within the catheter shaft, positioned tofacilitate positioning of the device. Such a system can also includeseparate optics for lumination and viewing, and flushing fluid supplyconduits for flushing the viewing fields.

[0028] The electrical conductor can also be positioned in the tissue tobe treated using ultrasound imaging from an ultrasound transducerpositioned at a distance from the target tissue or supported by theelectrical conductor or non-conducting sleeve.

[0029] The extent of heating can be monitored and controlled during theablative treatment using temperature sensors supported by the electricalconductor or non-conductive sleeve.

[0030] In another embodiment of the method of this invention fortreating a target tissue such as the prostate, two flexible stylets fromthe catheter are moved through catheter ports in the sidewall of thecatheter and through the urethra wall and surrounding tissue into theprostate target tissue to be treated, the catheter ports having axesforming an angle of less than 180° and for treatment in some tissue,less than 90°.

[0031] In a still further embodiment, a grounding plate is placed on theskin to direct the electrical current passing from one or moreelectrodes in a path through the target tissue to be ablated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032]FIG. 1 is a schematic cross-sectional drawing of the lower maleanatomy with one embodiment of the device of this invention in positionfor treatment.

[0033]FIG. 2 is a side view of the terminal housing portion of thecatheter of this invention with a plurality of extended stylets.

[0034]FIG. 3 is an end view of the terminal housing portion shown inFIG. 2.

[0035]FIG. 4 is a cross-sectional view of an alternative embodiment ofthe catheter of this invention.

[0036]FIG. 5 is a cross-sectional representation of an embodiment of aRF electrode stylet according to this invention.

[0037]FIG. 6 is a cross-sectional representation of an embodiment of amicrowave antenna stylet according to this invention.

[0038]FIGS. 7 and 8 are cross-sectional representations of an embodimentof the catheter of this invention with a stylet guide system foradjusting the stylet guide angle.

[0039]FIGS. 9 and 10 are detailed schematic cross-sectional views of aRF electrode stylet shown in FIG. 4 with a partially retracted sleevepositioned to treat tissue targeted for destruction while shieldingintervening tissue from treatment according to the method of thisinvention.

[0040]FIG. 11 is a schematic view of the assembly of control system,manual catheter control unit and catheter according to this invention.

[0041]FIG. 12 is an isometric representation of an embodiment of amanual control system of the system of this invention.

[0042]FIG. 13 is an isometric representation of an embodiment of a powerand control console of the system of this invention.

[0043]FIG. 14 is a view of an alternative four-probe embodiment of thedevice of this invention.

[0044]FIG. 15 is a side view of the distal probe end of the cathetershown in FIG. 14.

[0045]FIG. 16 is a cross-sectional end view of the probe end of thedevice shown in FIG. 15, taken along the line A-A.

[0046]FIG. 17 is a partial cross-sectional view of the probe end of thedevice of this invention, taken along the B-B of FIG. 16.

[0047]FIG. 18 is a cross-sectional view of the control end of the deviceshown in FIG. 14, taken along its central axis.

[0048]FIG. 19 is a cross-sectional view of the control end of the deviceshown in FIG. 18, taken along the line C-C.

[0049]FIG. 20 is a cross-sectional view of the control end of the deviceshown in FIG. 18, taken along the line D-D.

[0050]FIG. 21 is a side view of the non-conductive sleeve connector ofthe embodiment show in FIGS. 18 and 19.

[0051]FIG. 22 is a cross-sectional view of the non-conductive sleeveconnector shown in FIG. 21, taken along the line E-E.

[0052]FIG. 23 is a side view of the electrical conductor connector ofthe embodiment shown in FIGS. 18 and 20.

[0053]FIG. 24 is a cross-sectional view of the electrical conductorconnector shown in FIG. 23, taken along the line F-F.

[0054]FIG. 25 is a cross-sectional view of the distal end of thenon-conductive sleeve shown in FIGS. 15 and 16, taken along its centralaxis.

[0055]FIG. 26 is a top view of a two stylet alternative embodiment of anRF ablation catheter of this invention.

[0056]FIG. 27 is a top view of one embodiment of a stylet tip of thisinvention.

[0057]FIG. 28 is a side view of the single grind electrode tip shown inFIG. 27.

[0058]FIG. 29 is an end view of the electrode tip shown in FIG. 28.

[0059]FIG. 30 is a side view of an alternative double grind electrodetip.

[0060]FIG. 31 is an end view of the electrode tip shown in FIG. 30.

[0061]FIG. 32 is a top view of the handle portion of the ablationcatheter of FIG. 26.

[0062]FIG. 33 is a side view of the handle portion shown in FIG. 32taken along the line H-H with the bottom cover plate partially removed.

[0063]FIG. 34 is a bottom view of the handle portion shown in FIG. 32with the bottom cover plate removed.

[0064]FIG. 35 is a cross-sectional view of the handle portion takenalong the line J-J in FIG. 34.

[0065]FIG. 36 is a cross-section view of the central portion of thehandle portion shown in FIG. 33 in the stylet and sleeve retractedposition.

[0066]FIG. 37 is a cross-sectional view of the central portion of thehandle portion shown in FIG. 33 with the stylet and sleeve in anextended position.

[0067]FIG. 38 is a cross-sectional view of the central portion of thehandle portion shown in FIG. 33 with the stylet in an extended positionand the sleeve partially retracted therefrom.

[0068]FIG. 39 is a schematic view of a deployment of two stylets in aprostate showing stylet orientation for overlapping ablation zone methodof this invention.

DETAILED DESCRIPTION OF THE INVENTION

[0069] The device of this invention provides a precise controlledpositioning of a treatment stylet in a tissue targeted for treatment,destruction or sampling from a catheter positioned in the vicinity ofthe target tissue.

[0070] The term “stylet” as used hereinafter is defined to include bothsolid and hollow probes which are adapted to be passed from a catheterport through normal tissue to a target tissue. The stylet is shaped tofacilitate easy passage through tissue. It can be a solid wire, thinrod, or other solid shape or it can be a thin hollow tube or other shapehaving a longitudinal lumen for introducing fluids to or removingmaterials from a site. The stylet can also be a thin hollow tube orother hollow shape, the hollow lumen thereof containing a reinforcing orfunctional rod or tube such as a laser fiberoptic cable. The styletpreferably has a sharpened end to reduce resistance and trauma when itis pushed through tissue to a target site.

[0071] The stylet can be designed to provide a variety of medicallydesired treatments of a selected tissue. As a radiofrequency electrodeor microwave antenna, it can be used to ablate or destroy the targettissue. As a hollow tube, it can be used to deliver a treatment fluidsuch as a liquid to a target tissue. The liquid can be a simple solutionor a suspension of solids, for example, colloidal particles, in aliquid. Since the stylet is very thin, it can be directed from thecatheter through intervening normal tissue with a minimum of trauma tothe normal tissue.

[0072] The device and method of this invention provide a more precise,controlled medical treatment which is suitable for destroying cells ofmedically targeted tissues throughout the body, both within and externalto body organs. The device and method are particularly useful fortreating benign prostate hyperplasia (BPH), and the device and its useare hereinafter described with respect to BPH, for purposes ofsimplifying the description thereof. It will be readily apparent to aperson skilled in the art that the device and method can be used todestroy body tissues in any body cavities or tissue locations that areaccessible by percutaneous or endoscopic catheters, and is not limitedto the prostate. Application of the device and method in all of theseorgans and tissues are intended to be included within the scope of thisinvention.

[0073] BPH is a condition which arises from the benign replication andgrowth of cells in the prostate, forming glandular and stromal noduleswhich expand the prostate and constrict the opening of the prostaticurethra. Glandular nodules are primarily concentrated within thetransition zone, and stromal nodules within the periurethral region.Traditional treatments of this condition have included surgical removalof the entire prostate gland, digital removal of the adenoma, as well astransurethral resection of the urethral canal and prostate to removetissue and widen the passageway. One significant and seriouscomplication associated with the latter method is iatrogenic sterility.More recently, laser treatment has been employed to remove tissue,limiting bleeding and loss of body fluids. Balloons have also beenexpanded within the urethra to enlarge its diameter, with and withoutheat, but have been found to have significant limitations.

[0074] Microwave therapy has been provided with some success bypositioning a microwave antenna within the prostatic urethra andgenerating heat in the tissue surrounding the urethra with a microwavefield. Coolants are sometimes applied within the catheter shaft toreduce the temperature of the urethral wall. This necessitatescomplicated mechanisms to provide both cooling of the immediatelyadjacent tissues while generating heat in the more distant prostatictissue. This technique is similar to microwave hyperthermia. Similarly,radiofrequency tissue destruction with electrodes positioned within theurethra has limited applicability since it necessarily exposes theurethral wall to destructive temperatures. To avoid this, lowtemperature settings required to protect the urethra must be so low thatthe treatment time required to produce any useful effect is undulyextended, e.g. up to three hours of energy application.

[0075] One embodiment of the device of this invention uses the urethrato access the prostrate and positions RF electrode stylets directly intothe tissues or nodules to be destroyed. The portion of the styletconductor extending from the urethra to the target tissue is enclosedwithin a longitudinally adjustable sleeve shield which prevents exposureof the tissue adjacent to the sleeve to the RF current. Thus theablative destruction is confined to the tissues targeted fordestruction, namely those causing the constriction. Other aspects of theinvention will become apparent from the drawings and accompanyingdescriptions of the device and method of this invention. It will bereadily apparent to a person skilled in the art that this procedure canbe used in many areas of the body for percutaneous approaches andapproaches through body orifices.

[0076]FIG. 1 is a schematic cross-sectional drawing of the lower maleanatomy during use of the device and method of this invention. Theurethra 2 extends from the urinary bladder 4 through the prostate 6 andurogenital diaphragm 8. BPH is a condition characterized by constrictionof the portion of the prostatic urethra caused primarily byproliferation of benign glandular and stroma cells in the prostate.These nodules press the wall of the urethra inwardly, restricting theurethral diameter, and can press normal tissue outwardly, possiblyenlarging the prostate. Traditional treatments short of removal of theprostate have included either removal of tissue from the urethra toenlarge its lumen by resection or laser tissue destruction, or byexpansion and heating of the tissue surrounding the urethra to atemperature which causes cell death. The latter method is intended toreduce the swelling or enlargement of the prostate, and restore theurinary passage to at least a portion of its former diameter.

[0077] In the method of this invention, a catheter 14 with a styletguide 16 is passed upwardly through the urethra into the prostate. Theposition of the guide 16 is precisely controlled, using an ultrasoundimage, for example, obtained from signals received from the conventionalultrasound transducer 18 inserted into the rectum 20 adjacent to theprostate through the anal opening 22. The guide facilitates easypositioning of the stylet 17 into a precise location under ultrasoundimaging. Optionally, fiber optics can be used to position the styletguide.

[0078] The terminal portion of the catheter 14 can optionally have oneor more dilation balloons 30 and 32. Stylet sleeve 36 can be extendedthrough the urethra and other tissue to be protected, and an RFelectrode 38, as shown for example in this figure, can be extended deepinto the target tissue 28.

[0079]FIG. 2 is a side view and FIG. 3 is an end view of the terminalportion of one embodiment of a catheter of this invention. One or morestylet ports 40 are positioned between the unexpanded annular balloons30 and 32. An ultrasound transponder 42 can be positioned at theterminal end 44 for producing signals and images which can be used forprecise positioning of the stylet guide housing 16 in the prostate.Alternatively, an echogenic bubble can be incorporated into the distalhousing to aid in sonographic location of the stylet guide. One or moretemperature sensors 46, which can be conventional thermistors,thermocouples or optical fibers, are positioned along the catheter toprovide a temperature profile of the urethra adjacent to and preferablyon both sides the stylet section. This temperature profile can be usedby the operator to prevent the temperature of the urethral wall fromreaching a level which would cause cell destruction. These figures showboth balloon segments 30 and 32 and six stylets 36 in an extendedposition.

[0080] The catheter can be rotated about its central axis prior tostylet deployment to orient one or more of the stylets toward tissues tobe treated. After the catheter terminal housing 16 is advanced to atreatment position in the prostatic urethra, the annular balloons 30 and32 can be expanded in the urethra to stabilize the catheter and dilatethe urethral lumen. The stylets are extended through the urethral walland intermediate tissue until they are positioned in the tissue targetedfor treatment. The tissue targeted for BPH treatment may be nodules,normal tissue or both. The stylet passageways leading to ports 40 havean orientation such that their terminal axis forms an angle “a” whichcan be from about 20° to 160° and preferably from about 30° to 150° withthe central axis of the catheter in a plane therethrough. As will beexplained in greater detail hereinafter with regard to one embodiment ofthis invention, a non-conducting sleeve is then moved to expose thetarget tissue to controlled heating by an electric current or anelectromagnetic field to a destructive temperature above 45° C. andpreferably within the range of from 55° to 99° C.

[0081]FIG. 4 is a cross-sectional view of a catheter with an extendedstylet of one embodiment of this invention, and FIG. 5 is across-sectional enlarged view of the stylet tip shown in FIG. 4. In thisembodiment, the catheter 48 is connected to a stylet guide housing 50with a nose 52. The stylet 54 comprises a solid core needle 56 coaxiallypositioned within a tube 58, both of which are preferably constructed ofa highly flexible, conductive metal such as nickel-titanium alloy,tempered steel, stainless steel, beryllium-copper alloy and the like.Nickel-titanium and similar highly flexible, shaped memory alloys arepreferred. The needle 56 is axially or longitudinally moveable withinthe tube 58. The tube 58 is enclosed within an non-conductive,non-dielectric sleeve 60 which is longitudinally moveable along thetube. The guide housing 50 has a guide channel 61 which is curved topermit longitudinal advancement of the flexible stylet.

[0082] The sleeve 60 is connected to an annular cylinder 62 connectedwith a longitudinal thrust tube 64. Longitudinal movement of the thrusttube 64 causes a corresponding longitudinal movement of the sleeve 60along the tube 58. The sleeve movement is used to vary and control thelength of tube 58 and needle 56 exposed to surrounding tissue andcontrol the amount of energy delivered to the target tissue. Thematerial, insulating properties, dielectric properties and thickness ofthe sleeve 60 are selected to prevent heating energy delivery to tissuein contact therewith by shielding the tissue from the conductor. If thetissue is to be heated using radiofrequency current (300 to 750 kHz),the sleeve 60 must have sufficient thickness required to prevent bothcurrent flow and capacitance coupling with the tissue.

[0083]FIG. 6 is a cross-sectional representation of an embodiment of amicrowave antenna stylet according to this invention. This styletcomprises a coaxial central conductive needle wire 66 concentric with asurrounding conductive wire mesh or tube 68, the space therebetweenbeing filled with a conventional dielectric solid 70. The conductivewire mesh or tube 68 is enclosed within an insulating sleeve or coating72.

[0084] After the stylet is advanced into tissue to be treated, electricpower is delivered (900 to 2500 MHz), creating a electromagneticmicrowave field of destructive energy in the tissue surrounding theneedle antenna 66.

[0085]FIGS. 7 and 8 are cross-sectional, fragmentary representations ofan embodiment of the catheter of this invention with a stylet guidesystem for adjusting the stylet guide angle. The stylet guide housing124 has a stylet port 126. Within the guide housing 124, a styletpositioning block 128 is positioned for axial movement under the actionof torque and thrust rod 130. The stylet positioning block 128 has acurved stylet lumen containing the stylet 132. Optionally, a lowfriction, flexible guide tubing 134 extends from the positioning block128 to the port 126. In the position shown in FIG. 7, the positioningblock 128 is in a retracted position, orienting the stylet to extend atan acute angle “b” of approximately from about 20° and preferably 30° upto 90° with respect to the central axis of the guide housing.Advancement of the stylet 132 through the block 128, guide tubing 134and port 126 directs the stylet into tissue along the dotted line path136.

[0086] Advancement of the positioning block 128 as shown in FIG. 8forces the stylet 132 through a curved path having a smaller diameterthrough guide tubing 134 to the port 126. The stylet 132 is thendirected an obtuse angle which can be as high as about 160° with respectto the guide housing axis. Advancement of the stylet through the guideblock 128, guide tubing 134 and port 126 in this configuration directsthe stylet into tissue along the dotted line path 138.

[0087] As shown in FIGS. 7 and 8, the angular projection of the stylet132 can be oriented over a wide range of angles in a plane through thecentral axis of the stylet guide housing. It will be readily apparentthat rotation of the torque and thrust rod 130 about its central axiswill cause a corresponding rotation of the stylet guide housing anddeflection of the stylet in directions outside of the axial plane. Thiscombined with axial movement of the catheter to an optimum position in aduct and rotation of the catheter about its central axis yields aninfinite variety of stylet orientation angles. A combination of thesemovements provides greater choices of stylet angles so that the styletcan be advanced into target tissue at any angle from the catheter.

[0088]FIGS. 9 and 10 are detailed schematic cross-sectional views of aRF electrode stylet shown in FIG. 4 in use. After the catheter ispositioned in the urethra, the stylet 54 is advanced from the styletguide housing 50 through the prostatic urethra wall 71 to the targettissue 73 to be treated (outlined with a dotted line). Then, styletsleeve 60 is retracted to the position shown in FIG. 9, exposing theportion of the RF electrode positioned in the target tissue 73. RFcurrent is then directed from the electrode 56 and 58 through tissue 73to conventional grounding plates (not shown). In selected instances,more directed ablation can be obtained by using one or more of thestylets as the indifferent electrode and another of the styles as theactive electrode, thereby using only stylets to complete the dipole andnot using a grounding plate. The RF treatment is continued until thecells in the target tissue 73 have been destroyed.

[0089]FIG. 10 is a detailed schematic cross-sectional view correspondingto FIG. 9 in an optional second step following the procedure describedabove. Following destruction of the cells in target tissue 73, the RFelectrode sleeve 60 can be retracted along the stylet electrode 58 tothe stylet guide housing 50, exposing a length of RF electrode 74leading from the target tissue through prostatic urethra wall 71.Sufficient RF current is then applied to cauterize the surface of thetissue 76 (shown by dotted lines) immediately in contact with the entireexposed surface of the electrode 58. For example, this can be achievedwith a higher voltage and shorter duration treatment than is applied todestroy the cells of the target tissue. The stylet is then fullywithdrawn into the housing 50, leaving a drainage duct leading from thearea of the target tissue 73 to the prostatic urethra. This can providedrainage of the products of the treated target tissue 73 during thehealing process.

[0090] The transurethral needle ablation (TUNA) process of thisinvention is a process whereby a physician in a unique proceduredelivers radiofrequency or microwave energy to the hyperplastic tissuesof the prostate which develop in men with the condition known as BPH, orBenign Prostatic Hyperplasia.

[0091] This procedure is unique in that it is the first transurethralprocedure which selectively provides the capability ability to limit thetreatment to the constrictive tissue and spare the normal prostatictissue. This procedure also minimizes the trauma sustained by thesurrounding prostatic urethra, especially when compared to previouslyknown procedures for relieving obstructive uropathy due to BPH. Theprocedure could possibly be carried out under local anesthesia only,depending upon the rate of energy delivery and degree of pain sensationexperienced by the patient. When local anesthetic is adequate, theprocedure can be performed in the physician's office. Local anestheticcould be delivered or applied in the form of a lubricant containing atopical anesthetic such as lidocaine mixed with K-Y jelly.

[0092] If substantial pain will be experienced by the patient, thepatient must be sedated in addition to application of topical localanesthetic. This procedure can be provided on an outpatient basis andwould require a short term (2-6 hour) observation. If the procedure andpatient require greater pain control, then spinal anesthesia or ageneral anesthesia may be used for patients which qualify for their use.This would mandate that the procedure be carried out in the operatingroom, would require a recovery room, and could possibly requirein-patient care in certain circumstances. The previously known prostateresection (TURP) generally requires use of general or spinal anesthesiaand in-patient hospital care following the treatment.

[0093] The BPH method of this invention can be carried out in thefollowing manner, using a RF electrode stylet embodiment of thisinvention. A male patient is given the appropriate pre-procedurepreparation which would usually require a fleets enema or bowelpreparation. This would clear the rectal vault of stool in order tobetter place a rectal ultrasound probe, if used, and to assure bettervisualization. Appropriate anesthetic, would then be administered. Aconventional grounding plate is then placed in contact with the patient.The rectal probe would then be inserted to the level of the prostate inorder to obtain an ultrasound image of the prostate. The procedure couldbe done without the use of rectal ultrasound, using only directvisualization at the discretion of the operator. The urethral catheterwould then be inserted in a fashion similar to that used for inserting aFoley catheter. First the glans and the penile shaft would be bathed inbetadine or other disinfectant. The rest of the groin adjacent areas aredraped with sterile towels in the usual fashion. Then using aseptic orsterile technique, the shaft of the penis is grasped in one hand whilethe catheter is inserted into the urethral meatus and advanced until ithas reached to desired position in the prostatic urethra. The cathetermovement during its advancement through the urethra can be monitoreddirectly with the ultrasound image. If direct visualization with fiberoptics is used, the appropriate landmarks are located and identified,i.e., verumontanum and bladder neck, etc. If this has not beenaccomplished earlier, the various electrical and mechanical connectionsbetween the catheter and the control assembly are connected at thisstage.

[0094] The RF electrode stylet is then deployed under direct vision orultrasound imaging into a selected target tissue. This requires that thephysician locate the target area to be treated, rotate, advance and/orretract the catheter as necessary to orient the stylet guide port towardthe target area. The stylet, preferably completely enclosed in itsinsulating sleeve or sheath, punctures and penetrates the epitheliallining of the prostatic urethral, traveling through prostatic tissue tothe target tissue, and penetrating the tissue to the desired depth.Local anesthetic can be infiltrated into the target tissue through thecentral lumen of the stylet as the stylet is advanced. The insulatingsleeve is then retracted the amount required to expose a preciseselected length of the RF electrode in the target tissue. This amount isselected to effect the degree and volume of tissue destruction desired,the volume increasing as the length of the exposed electrode increases.This volume is selected based on the size of the target tissue to beablated and the relative position of the electrode stylet in the targettissue. The distance the sleeve is withdrawn can be measured external tothe body using a conventional measuring devices such as a scale.

[0095] The electrode stylet is then energized from an RF energy sourceby closing a conventional switch. Preferably, the time and/or powerlevels are preset by the control unit. The RF energy is delivered to thetarget tissue for a preselected time, monitoring the advance of thedestructive lesion by the rectal ultrasound image. Impedance is alsomonitored, and when or if it exceeds a preset value, the power supplycan be reduced or terminated. The temperature of the catheter surfaceadjacent the urethral lining, the sleeve and even the exposed electrodecan also be monitored using temperature sensors attached to thesecomponents to precisely control the volume of the lesion and preventexcessive heating of normal tissue.

[0096] After the target tissue destruction has proceeded to the desiredstage, the physician has two options. The stylet electrode can bewithdrawn into the catheter to facilitate quick healing and rapidsealing of the urethral puncture site. Alternatively, the physician cancreate a temporary physiological drainage capillary which would allowany fluid or debris accumulating in the ablated target tissue to draininto the urethra. This physiological drainage capillary can be createdafter target tissue destruction by withdrawing the insulating sleeve orsheath back into the urethral catheter as shown in FIG. 10. Theconductive stylet is then energized to a level sufficient to “sear” orcauterize a small hollow channel through the tissue. This channel willeventually scar and fibrose, or it will seal and heal. The conductivestylet is then entirely withdrawn, and the catheter is slowly andcarefully withdrawn from the urethra. The patient is then monitored andtreated as appropriate for the type of anesthesia delivered and thecondition of the patient.

[0097]FIG. 11 is a schematic view of the assembly of the control system150, a manual catheter control unit 152, catheter 154, and power footcontrol 156. The power foot control functions can be accomplished bynumerous other methods to include manual digital switches on control box150 and by a trigger device on the catheter handle 152. The manualoperation of the catheter assembly is controlled from a manual controlunit shown in greater detail in FIG. 12, with the power control andtemperature displays being provided in the control system 150 shown ingreater detail in FIG. 13.

[0098]FIG. 13 is an isometric representation of an embodiment of amanual control system of the system of this invention. The manualcontrol 12 has a pistol grip 158 with a tube 160 leading to the consoleshown in FIG. 14. The tube 160 houses RF or microwave power supplycables, temperature sensors, ultrasound transducer power and signaldelivery leads, balloon inflation fluid and vacuum lumens.

[0099] Rocker switches 162 and 164 provide control over the inflation ordeflation of balloons 30 and 32 (FIGS. 1 and 2). Tab 166 sliding ingroove 168 is connected to a stylet 62, advancing it into the a targettissue as the tab 166 is moved forward. Rotary dial 170 is attached tothe catheter 154 and can be used to rotate the catheter for orientationof the stylet or stylets. Window 172 has graduations showing thepercentage of balloon expansion.

[0100]FIG. 13 is an isometric representation of an embodiment of a powerand control console 150 of the system of this invention. The housing ofthis console has a display panel 174 with digital readout displays 176showing power to the stylet, antenna temperatures, tissue temperatures,impedance values, and other data, for example. The housing can support asealed membrane switch panel 178 having system control buttons 179.Power cord 180 leads to a standard power outlet. Cable 182 leads to themanual catheter control unit 152 shown in FIG. 12. Cable 184 leads to aoptional power foot control unit. Cable 185 leads to the grounding patchfor use in unipolar systems.

[0101]FIG. 14 is a view of an alternative four-probe embodiment of thedevice of this invention. The device comprises a handle portion 180 anda catheter portion 182. The catheter portion 180 includes an elongatedcatheter 184 having a distal catheter probe end 186. A plurality ofstylets 188 extend outwardly from the probe end 186. The end 190 of thehandle portion 180 is attached to the proximal end of the catheter 182,and manual control tabs 192 and 194 mounted thereon for slidingengagement with side walls of the handle portion. Using the handle 180for control, the catheter is introduced into a body duct, vascularstructure or canal such as the urethra, for example, and pushed up theduct to the treatment position, for example a position adjacent theprostate. Stylets 188 are individually and selectively passed outwardfrom the distal end 190 through surrounding tissue to the target tissueto be treated by movement of respective manual control tab pairs 192 and194. When the stylets are electrical conductors surrounded by moveablesleeves, the sleeves can be retracted from the end of the stylets bymovement of manual control tabs 194 as described in greater detailhereinafter. Preferably, the proximal portion of the catheter 182 ispreferably stiff to facilitate control during insertion in a body duct,while the distal portion is preferably flexible to allow the catheter topass through curved duct portions.

[0102]FIG. 15 is a side partially sectioned view of the distal probe endof the catheter shown in FIG. 14 with stylets extended from the sideports, and FIG. 16 is a cross-sectional end view of the probe end of thedevice shown in FIG. 15, taken along the line A-A. The distal cathetertip 186 is a stylet guide housing having a lateral surface 196 whichmerges with a tapered tip portion 198. The stylets 188 extend outwardlyfrom the lateral surface 196 and comprise an electrode 200 and moveablesurrounding sleeve 202. The proximal portion 204 of the stylet guide isconnected to the distal end 206 of the catheter stem 208. Further styletports such as the port from which stylet 203 extends are positioned at agreater distance from the tip 198 than ports 216. The embodiment shownin FIGS. 15 and 16 comprises two sets of stylets, each pair extendingfrom ports in a common plane perpendicular to the catheter central axis.It will be readily apparent to a person skilled in the art that otherstylet arrays such as a longitudinal array or a spiral array can also beused, and these variations are considered to be fully within the scopeof this invention.

[0103] The catheter stem 208 includes an outer tubular housing 210 whichencloses a plurality of stylets stems 212 disposed in a parallelrelationship. As can be seen from FIG. 16, the individual stylets aredirected outward in paths which have axes forming angles with eachother. oppositely disposed stylets can form an angle of up to 180° whilein the configuration shown, the axis of adjacent stylets can form anangle of up to 90° for example.

[0104]FIG. 17 is a partial cross-sectional view of the probe end of thedevice of this invention, taken along the B-B of FIG. 16. The stylet isdirected through a stylet guide means 214 in the distal catheter end 186which leads from a path in the proximal catheter end 204 parallel withother stylet guides to a lateral orientation through stylet port 216. Tofacilitate longitudinal movement of the stylet through the guide path,the guide path preferably has a curved portion 218 extending to the port216. The curved path optionally has a radius which is sufficient todeflect the deployed, extended stylet to the desired angle, that is, aradius of up to 0.5 cm, depending upon the diameter of the catheter.optimally, the guide path also has a reverse curved portion 220 whichextending from the axially parallel path in the proximal catheter end214 outwardly away from the port 216 to the beginning of the curved path218.

[0105] The distal tip 198 of the catheter can have a hollow space orbubble 222 which reflects ultrasound, permitting its easy identificationwith ultrasound generated by a rectal probe as shown in FIG. 1.Alternatively, a transponder can be mounted in the distal tip 198.

[0106]FIG. 18 is a cross-sectional view of the handle and control end ofthe device shown in FIG. 14, taken along its central axis. The controlhandle 180 is attached to the control end of the catheter stem 208. Thehandle 180 comprises a housing having a distal end forming an axialsleeve 224 enclosing the proximal end 226 of the catheter stem 208. Theproximal end 226 is held in place by setscrew 228 extending through thesleeve 224. Manual engagement means 192 and 194 engage lateral handlehousing walls 230 and 232, and are mounted for sliding engagement withrespective slots 234 and 236 in the respective housing walls. Theytranslate the manual motion into longitudinal motion of the stylet inthe stylet guide means.

[0107]FIG. 19 is a cross-sectional view of the control end of the deviceshown in FIG. 14, taken along the line C-C. Referring to both FIGS. 18and 19, finger engaging sleeve movement tabs 192 are connected toconnecting slide portion 238 extending through a respective longitudinalslot 234 and a inner portion 240 which forms a sliding engagement withthe interior surface of the handle wall 230. Slot 242 in the connectingslide portion receives a pin 244 extending through a sleeve connector246. Axial movement of the tab 192 thus effects an axial movement ofcorresponding sleeve 248 in the handle. Each side of the handle can havea pair of longitudinal, parallel slots to accommodate manual tabs forboth sleeve and electric conductor.

[0108]FIG. 20 is a cross-sectional view of the control end of the deviceshown in FIG. 14, taken along the line D-D. Referring to FIGS. 18 and20, finger engaging electrical conductor movement tab 194 is connectedthrough a connecting slide portion 250 extending through a respectivelongitudinal slot 236 to a inner portion 252 which forms a slidingengagement with the interior surface of the handle wall 232. Slot 254receives a pin 256 extending through a electrical conductor connector258. Axial movement of the tab 194 thus effects an axial movement of thecorresponding electrical conductor 260 in the handle.

[0109] Movement of adjacent tabs 192 and 194 advance the correspondingsleeve and electrical conductor together through the correspondingstylet guide, out the corresponding stylet port, and through interveningtissue to the target tissue to be ablated. Reverse movement of thesleeve tab 192 then retracts the sleeve to expose a selected area of theelectrical conductor surface in the tissue, preparatory to ablation.

[0110]FIG. 21 is a side view of the non-conductive sleeve connector ofthe embodiment show in FIGS. 18 and 29, and FIG. 22 is a cross-sectionalview of the non-conductive sleeve connector shown in FIG. 21, takenalong the line E-E. Connecting pin 244 extends through a hole in thesleeve connector 246. An axial edge of the sleeve connector 246 isconnected to the proximal end portion 248 of the sleeve.

[0111]FIG. 23 is a side view of the electrical conductor connector ofthe embodiment show in FIGS. 18 and 20, and FIG. 24 is a cross-sectionalview of the electrical conductor connector shown in FIG. 23, taken alongthe line F-F. Connecting pin 256 extends through a hole in theelectrical conductor connector 258. An axial edge of the electricalconductor connector 258 is connected to the proximal end portion 260 ofthe electrical conductor.

[0112]FIG. 25 is a cross-sectional view of the distal end of thenon-conductive sleeve shown in FIGS. 16-18, taken along its centralaxis. The non-conductive sleeve 202 comprises a tapered leading tip 262and a rigid proximal portion 264. A flexible portion 266 extends betweenthe leading tip 262 to the rigid proximal portion 264. The flexibleportion 266 can be any flexible configuration such as a spiral coil,wire braid, stainless steel tube, or any other flexible constructionwhich yields a catheter which has the required flexibility and torquestrength. If the flexible portion 266 and the rigid proximal portion 264are made of a conductive materials such as metal, they can be coveredwith an insulating sleeve 268. The annular ridges 270 in the rigidproximal portion and the flange 272 in the tip engage the sleeve 268,securing the sleeve in place. The inner lumen 274 of the non-conductivesleeve 202 receives the electrical connector 200. A temperature sensorsuch a thermistor 271 can be mounted on the tip to provide localtemperature information. An ultrasound transponder 273 can also bemounted on the tip to provide a signal useful for precise positioning ofthe stylet tip in a tissue to be ablated.

[0113]FIG. 26 is a top view of a two stylet preferred embodiment of anRF ablation catheter of this invention. The flexible catheter 300,attached to handle 302, has a terminal stylet guide 304 with two stylets306 and 308. The handle has stylet sleeve tabs 356 and electrode tabs354 as will be described in greater detail hereinafter. The handle isalso connected to a visual monitor 301 and RF power connector 303,transponder connector 305 and thermocouple connector 307. The portionsof the catheter 300 leading from the handle 302 to the stylet guide tip304 can optionally has a graduated stiffness. For example, the cathetercan be designed to be more stiff near the handle and more flexible nearthe tip, or any other stiffness profiles. The catheter can beconstructed of an inner slotted stainless steel tube with outer flexiblesleeve such as is described in copending application Serial No. 790,648filed Aug. 11, 1991 (corresponding to published Australian patentapplication Serial No. 9210858), the entire contents of which areincorporated herein by reference. It can also be made of coiled orbraided wire to which an outer sleeve is bonded.

[0114]FIG. 27 is a top view of the stylet tip of the embodiment shown inFIG. 26, FIG. 28 is a side view of the single grind electrode tip shownin FIG. 27, and FIG. 29 is an end view of the electrode tip shown inFIG. 28. In this embodiment, the sharpened tip 326 and leading cuttingedges 328 and 330 are formed by grinding one surface of the tip, thecutting edges forming an angle, “d”, of from 15° to 45° and preferablyfrom 25° to 35° with a line parallel with the central axis of the tip.The proximal surface of the tip forms a shoulder 332 which the leadingor distal edge 334 of the sleeve 336 abuts, preventing movement of thesleeve 336 over the sharpened tip. The sleeve 336 can also supporttemperature sensors such as a thermistor 338 and a ultrasoundtransponder 340.

[0115]FIG. 30 is a side view of an alternative double grind electrodetip, and FIG. 31 is an end view of the electrode tip shown in FIG. 30.In this embodiment, the sharpened tip 342 and leading cutting edges 344and 346 are formed by grinding both surfaces of the tip. The proximalsurface of the tip forms a shoulder 348 which the leading or distal edgeof a sleeve (not shown) abuts, preventing movement of the sleeve overthe sharpened tip. The forward cutting edges of this embodiment makelittle if any contact with the inner surface of the stylet guide in thecatheter tip, preventing dulling of the cutting edge.

[0116]FIG. 32 is a top view of the handle portion of the ablationcatheter of FIG. 26. The handle 302 has an upper housing plate 350 uponwhich stylet sleeve positioning slides 352 and electrode positioningslides 354 with manual tabs 356 and 358 are mounted for sliding movementin the direction of the central axis of the housing. The position of theleading edges 360 of the slides relative to the graduated markings 362on the housing plate surface are used to determine the distance thesleeve and stylet have been advanced from the stylet guide toward tissueto be treated.

[0117]FIG. 33 is a side view of the handle portion shown in FIG. 32taken along the line H-H with the bottom housing cover plate partiallyremoved. The proximal end of the catheter 300 passes through acylindrical hole 364 in the cylindrical knurled knob 366 and cylindricalreceptor 368 formed by the opposed hemicylindrical surfaces in thedistal ends of the upper housing plate 350 and lower housing plate 370.The proximal end of the knurled knob 366 has a cylindrical receptor 372which forms a sliding fit with a cylindrical projection 374 formed bythe distal ends of the housing plates 350 and 370. Setscrew 376 securesthe knob 366 to the catheter 300 so they rotate together as a unit. Pin378 extends through the knob 366 into an annular groove 380, allowingrotation but preventing axial movement of the knob 366 relative to thecylinder 374. The angular position of the knob 366 relative to thehousing plate 350 is shown by the position of the arrow 382 relative tothe graduations 384 on the knob (FIG. 32). Knurled knob 386 treadinglyengages hole 388 in the housing plate 350. When the catheter knob 366has been turned to rotate the catheter 300 (and the stylet guide on itsend) to a desired stylet orientation, advancement of the knob 386against the catheter surface 390 secures its angular position. Thestylets are then advanced through surrounding tissue to the depthdesired, as indicated by graduations 362.

[0118]FIG. 34 is a bottom view of the handle portion shown in FIG. 32with the catheter, distal knob and bottom cover plate removed, and FIG.35 is a cross-sectional view of the handle portion taken along the lineJ-J in FIG. 34. Stylet movement guide plates 392 and 394 are securelymounted in terminal end receptors 396 in the inner surfaces of upperhousing plate 350. Each of the guide plates 392 and 394 has a sleeveguide slot 398 and a electrode guide slot 400 therein. Screws 402 extendthrough sleeve guide slots 400 and threadingly engage the sleeve guideblocks 404. Axial movement of the screws 402 and guide blocks 404attached thereto is limited by the length of the slots 398. Sleeveconnector 406 attached to stylet sleeve 408 is secured to the guideblock 404 by screw 410. Slide plate 412 mounted for sliding movement ina slot 414 in the housing plate 350 is secured to guide block 404.Screws 416 extend through sleeve guide slots 400 and threadingly engagethe electrode guide blocks 418. Axial movement of the screws 416 andguide blocks 418 attached thereto is limited by the length of the slots400. Electrode connector 420 attached to stylet electrode 422 is securedto the guide block 418 by screw 424. Slide plate 354 mounted for slidingmovement in a slot 426 in the housing plate 350 is secured to guideblock 418.

[0119]FIG. 36 is a cross-section view of the central portion of thehandle portion shown in FIG. 33 in the stylet and sleeve retractedposition (corresponding to the positions in FIG. 32). FIG. 37 is across-sectional view with the stylet and sleeve in an extended position,and FIG. 38 is a cross-sectional with the stylet in an extended positionand the sleeve partially retracted therefrom. The stylets are extendedafter the catheter is inserted to place the stylet guides in a positionlaterally adjacent the target tissue to be treated and the catheter hasbeen rotated to orient the stylet guide outlets in the direction of thetarget tissue. The stylets are extended through intervening tissue tothe target tissue by moving the manual tabs 356 and 358 toward thedistal end of the handle as shown in FIG. 37. This effects simultaneousmovement of the stylet sleeve 408 and electrode 422. After the extensionhas proceeded to the extent required to place the tip of the electrode422 in the target tissue, the sleeve 408 is retracted to the positionshown in FIG. 38 by moving the manual tab 358 in the proximal directionto the extent required to expose the desired portion of the electrode asindicated by graduations 362 (FIG. 32). The RF current is then appliedto the electrodes until the desired ablation has been achieved. Withthis embodiment, two stylets can be extended, sleeves retracted, and theablation achieved either concurrently or sequentially.

[0120]FIG. 39 is a schematic view of a deployment of two stylets in aprostate showing stylet orientation for overlapping ablation zone methodof this invention. For purposes of illustration but not by way oflimitation, the prostate has been selected for this explanation, andapplication of this method and assembly to other areas of the body areintended to be included.

[0121] The tissues to be treated for the treatment of BPH are located inthe transition zone 428 of the prostate. A catheter of this invention430 has been inserted up the urethra 432 to a position adjacent theprostate. Two stylets 434 and 436 have been passed through the urethrawall 432 and surrounding tissue into the target tissue, and thenon-conducting sleeves 438 and 440 have been retracted to expose aportion of the respective electrical conductors 442 and 444 at the endof each stylet. The angle between the axes of the stylets in thisembodiment, “e”, is less than 180°, preferably less than 110°. For mostoverlapping ablations, angles of 15° to 90°, and more usually from 20°to 70° are most practical. A Grounding plate (not shown) is placed onthe body exterior.

[0122] When electrodes 442 and 444 are supplied with RF current, thecircuit from the electrodes to a grounding plate is closed. The currentdensity flowing through the tissue passes through the target tissue tobe treated, creating lesions having the approximate cross-sectionalshape of overlapping zones 446 and 448. The current density rapidlydecreases as a function of distance, limiting the size of the lesions.In this manner, lesions can be caused to overlap to form a largerlesion, increasing the efficiency of the treatment. It will be readilyapparent that these processes can be carried out concurrently, asdescribed, or sequentially, and these variations are intended to beincluded in this invention.

[0123] Although preferred embodiments of the subject invention have beendescribed in some detail, it is understood that obvious variations canbe made without departing from the spirit and the scope of the inventionas defined by the appended claims.

We claim:
 1. A medical probe device comprising a catheter having acontrol end and a probe end, the probe end including a stylet guidehousing having at least one stylet port in a side thereof and styletguide means for directing a flexible stylet outward through at least onestylet port and through intervening tissue to a target tissue, a styletpositioned in at least one of said stylet guide means, the styletcomprising an electrical conductor enclosed within a non-conductivesleeve, the electrical conductor being a radiofrequency electrode.
 2. Amedical probe device of claim 1 wherein the non-conductive sleeve ismounted for longitudinal movement on the electrical conductor to exposea selected portion of the electrical conductor surface in the targettissue.
 3. A medical probe of claim 1 wherein the electrode is a tubehaving an axial lumen extending therethrough.
 4. A medical probe ofclaim 3 wherein a solid wire is disposed in the axial lumen forlongitudinal movement therein.
 5. A medical probe of claim 1 wherein thestylet guide housing includes at least two of said stylet ports.
 6. Amedical probe of claim 1 wherein the stylet guide housing includes twoof said stylet ports positioned approximately in a plane perpendicularto the central axis of the housing.
 7. A medical probe of claim 1wherein a ultrasound reflecting means or an ultrasound transponder meansis positioned in the distal end of the catheter for providing a signalindicating the position of the catheter in the body.
 8. A medical probeof claim 1 including a temperature sensor means mounted on the styletguide housing for indicating the temperature in the tissue adjacent tothe guide housing.
 9. A medical probe of claim 1 including an ultrasoundtransponder means mounted on the distal end of the non-conductive sleevefor emitting a signal indicating the position of the stylet in the body.10. A medical probe of claim 1 including a temperature sensor meansmounted on the distal end of the non-conductive sleeve for indicatingthe temperature of tissue at the distal end of the sleeve.
 11. A medicalprobe of claim 1 wherein the electrical conductor is a highly flexiblemetal.
 12. A medical probe of claim 11 wherein the highly flexible metalis nickel-titanium alloy.
 13. A medical probe of claim 1 wherein thestylet guide means defines a stylet path from an axial orientation inthe catheter through a curved portion to a lateral orientation at thestylet port.
 14. A medical probe of claim 13 wherein the curved portionhas a radius which is sufficient to permit sliding deployment of thestylet in the stylet guide and deflect the stylet during deployment tothe desired angle.
 15. A medical probe of claim 14 wherein the curvedportion has a radius of up to 0.5 cm.
 16. A medical probe of claim 15wherein the stylet guide means defines a stylet path having a firstcurved portion extending in a direction away from the stylet port and asecond curved portion, continuing from the first curved portion andextending to the stylet port.
 17. A medical probe of claim 13 whereinthe stylet guide means defines at least two non-intersecting styletpaths from parallel axial orientations in the catheter through curvedportions to lateral orientations at stylet ports having central axesforming an angle of up to 180°.
 18. A medical probe of claim 17 whereinthe angle is less than 180°.
 19. A medical probe of claim 17 wherein theangle is less than 90°.
 20. A medical probe of claim 17 in combinationat least one grounding plate, the grounding plate being adapted to drawelectrical current passing from the electrodes through target tissue tobe ablated.
 21. A medical probe of claim 13 wherein the stylet guidemeans defines at least four non-intersecting stylet paths from parallelaxial orientations in the catheter through curved portions to lateralorientations at stylet ports extending outward at approximately 90°interval directions about the axis of the catheter.
 22. A medical probeof claim 1 wherein the non-conductive sleeve comprises a leading tip, arigid proximal control section, and a flexible portion extending fromthe leading tip to the rigid proximal control section, enabling thesleeve to be extended through a curved path from an axial orientation toan orientation extending outward through a stylet port.
 23. A medicalprobe of claim 22 wherein the leading tip is tapered inward to convergetoward its terminal end.
 24. A medical probe of claim 22 wherein theflexible portion comprises a spiral coil or wire braid.
 25. A medicalprobe of claim 24 wherein the flexible portion is made of conductivematerial enclosed in an outer non-conductive material.
 26. A medicalprobe of claim 1 wherein the electrical conductor has a sharp blade tip.27. A medical probe of claim 26 wherein the distal portion of the sharpblade tip defines a shoulder, and the distal end of the sleeve tapersinward to a tip having a diameter that does not significantly exceed thethickness of the shoulder.
 28. A medical probe of claim 1 wherein thedistal portion of the catheter is more flexible than the proximalportion thereof, facilitating its passage through curved ducts.
 29. Amedical prove of claim 28 wherein the more flexible portion of thecatheter comprises a spiral coil, wire braid or slotted tube having asmooth outer layer.
 30. A medical probe of claim 1 comprising a controlhandle attached to the control end of the catheter, and stylet movementmeans attached to a stylet and engaging the handle for longitudinalmovement of the stylet in the stylet guide means.
 31. A medical probe ofclaim 30 wherein the stylet movement means comprises manual engagementmeans for translating manual motion into longitudinal motion of thestylet in the stylet guide means.
 32. A medical probe of claim 2comprising a control handle attached to the control end of the catheter,a non-conductive sleeve movement means attached to a non-conductivesleeve and an electrical conductor movement means attached to theelectrical conductor enclosed therein, the non-conductive sleevemovement means comprising means for translating manual motion intolongitudinal motion of the non-conductive sleeve in the stylet guidemeans, the electrical conductor movement means comprising means fortranslating manual motion into longitudinal motion of the electricalconductor in the non-conductive sleeve, the non-conductive sleevemovement means and the electrical conductor movement means engaging thehandle for movement thereon.
 33. A medical probe of claim 32 wherein thenon-conductive sleeve movement means and the electrical conductormovement means include separate, adjacent manual movement means mountedon the handle for both separate and coordinated movement thereon.
 34. Amedical probe of claim 32 wherein the control handle has at least twoparallel longitudinal slots through a wall thereof, the manual movementmeans each including a finger engaging surface connected to a slideextending through one of the longitudinal slots to a connector in theinterior of the housing, the connector being attached to a respectivenon-conductive sleeve or electrical conductor.
 35. A medical probedevice comprising a catheter having a control end and a probe end, theprobe end including a stylet guide housing having at least one styletport in a side wall thereof and guide means for directing a flexiblestylet outward through the stylet port and through intervening tissue toa target tissue.
 36. A medical probe of claim 35 wherein the stylet isdirected outward at an angle in a plane through the central axis of thecatheter housing of from about 20° to 160° with the central axis of thestylet guide housing.
 37. A medical probe of claim 35 wherein thecatheter includes a stylet guide lumen communicating with the styletport and a stylet positioned in said stylet guide lumen for longitudinalmovement from the port through intervening tissue to a target tissue.38. A medical probe of claim 35 wherein the stylet is an electricalconductor enclosed within a non-conductive layer, the electricalconductor being a radiofrequency electrode.
 39. A medical probe of claim38 wherein the non-conductive layer is a sleeve which is longitudinallymoveable on the electrical conductor to expose a selected portion of theelectrical conductor surface in the target tissue.
 40. A medical probeof claim 35 wherein the stylet is a microwave antenna.
 41. A medicalprobe of claim 35 wherein the stylet is a cannula having an axialtreatment fluid supply lumen extending therethrough and the catheter hasa treatment fluid transport lumen communicating with the treatment fluidsupply lumen.
 42. A medical probe of claim 35 wherein the stylet guidehousing includes an array of said stylet ports.
 43. A medical probe ofclaim 35 wherein the catheter includes an inflation fluid delivery lumenextending therethrough, and the probe end includes at least oneinflatable balloon in communication with the inflation fluid deliverylumen.
 44. A medical probe of claim 43 wherein the inflatable balloon isan annular dilation stabilizer balloon means for expanding outwardlyagainst a duct wall and is positioned adjacent a stylet port.
 45. Amedical probe of claim 35 wherein an ultrasound transponder is attachedto a distal end of the stylet.
 46. A medical probe of claim 35 whereinan ultrasound transducer is attached to a distal end of the probe.
 47. Amedical probe of claim 35 wherein the stylet includes a radiofrequencyelectrode or microwave antenna, and at least one temperature sensor isattached to at least one of the probe end, stylet guide housing andstylet.
 48. A medical probe of claim 47 wherein the temperature sensoris a thermistor, thermocouple or fiber optic cable.
 49. A medical probeof claim 35 wherein the stylet comprises a fiber optic cable means forlaser treatment.
 50. A method for medical treatment of a tissue masscomprising: a) introducing a catheter to a zone adjacent to the targettissue to be treated; b) moving a flexible stylet from the catheterthrough a catheter port in the sidewall of the catheter and throughsurrounding tissue into a target tissue to be treated; and c) performingthe medical treatment of the target tissue with the stylet.
 51. A methodof claim 50 wherein the stylet is a radiofrequency electrode at leastpartially enclosed within a non-conductive sleeve means for preventingsignificant transfer of current from the electrode to tissue surroundingthe sleeve, and the medical treatment energy comprises generating heatin the target tissue by passing electric current from the electrode intothe target tissue.
 52. A method of claim 51 comprising moving thenon-conductive sleeve means from a preselected area of the electrode inthe target tissue to be treated and generating heat in the target tissueby passing electrode current from the preselected area of the electrodeinto the target tissue.
 53. A method of claim 50 wherein the stylet is amicrowave antenna.
 54. A method of claim 50 wherein the electricalconductor is extended into the tissue to be treated, positioned by useof ultrasound imaging.
 55. A method of claim 54 wherein the ultrasoundimaging is obtained with an ultrasound transponder positioned on thestylet.
 56. A method of claim 54 wherein the ultrasound imaging isobtained with an ultrasound transducer positioned at the end of thecatheter.
 57. A method of claim 50 wherein the temperature of the targettissue being treated is monitored during the treatment using atemperature sensor attached to the catheter or flexible stylet.
 58. Amethod for ablative treatment of a target tissue without exposing tissuesurrounding the target tissue to destructive temperatures comprising: a)advancing an electrical conductor through surrounding tissue into atarget tissue to be ablated, the conductor being a flexible styletsurrounded by a moveable non-conductive sleeve means for preventingsignificant transfer of energy from the conductor to tissue surroundingthe sleeve; and b) moving the non-conductive sleeve means to remove itfrom a preselected portion of the conductor positioned in the body massto be treated, and generating heat in the body mass from an electriccurrent from the preselected portion of the conductor.
 59. A method ofclaim 58 including the additional steps for creating a drainage canalfrom the treated target tissue comprising: c) retracting thenon-conductive sleeve means from a length of the conductor whichcorresponds to the position and length of the desired drainage canal,and d) generating sufficient destructive heat in the tissue adjacent theexposed conductor from an electric current from the exposed conductor toform a canal.
 60. A method for treating a target tissue such as theprostate comprising: a) introducing a catheter up the urethra to a zoneadjacent to the prostate target tissue to be treated; b) moving twoflexible stylets from the catheter through catheter ports in thesidewall of the catheter and through the urethra wall and surroundingtissue into the prostate target tissue to be treated, the catheter portshaving axes forming an angle of less than 180°; and c) performing themedical treatment of said target tissue with the stylet.
 61. A method ofclaim 60 wherein the angle is less than 110°.
 62. A method of claim 60wherein the stylets are flexible electrical conductors surrounded bymoveable non-conductive sleeves for preventing significant transfer ofenergy from the conductors to tissue surrounding the sleeves, and thenon-conductive sleeves are retracted to remove them from preselectedportions of the conductors positioned at the prostate to be treated, andgenerating heat in the prostate from electric current from thepreselected portions of the conductors.
 63. A method of claim 60 whereinthe stylets are flexible electrical conductors surrounded by anon-conducting sleeve means for preventing significant transfer ofenergy from the conductor to tissue surrounding the sleeve, andgrounding plates are placed on the skin in positions which drawelectrical current passing from the electrodes through target tissue tobe ablated, and ablating heat is generated in the target tissue fromelectrical current passing through the electrodes to the groundingplates.
 64. A method for ablative treatment of a target tissue withoutexposing tissue surrounding the target tissue to destructivetemperatures comprising: a) advancing an electrical conductor throughsurrounding tissue into a target tissue to be ablated, the conductorbeing a flexible stylet surrounded by a non-conductive sleeve means forpreventing significant transfer of energy from the conductor to tissuesurrounding the sleeve; b) placing a grounding plate on the skin todirect an electrical current passing from the electrode through thetarget tissue to be ablated; and c) generating heat in the target tissuefrom an electrical current passing from the electrode to the groundingplate.
 65. A method of claim 64 wherein the stylets are flexibleelectrical conductors surrounded by moveable non-conductive sleeves forpreventing significant transfer of energy from the conductors to tissuesurrounding the sleeves, and the non-conductive sleeves are retracted toremove them from preselected portions of the conductors positioned inthe prostate, and generating heat in the prostate from electric currentfrom the preselected portions of the conductors.